Microstructures and Properties of WC/Natural Zeolite Composites

WC/zeolite nanocomposites were prepared by ball―milling a mixture of ammonia metatungsten (AMT) and zeolite and then reducing the ball―milled precursor under mixed CH4/H2 atmosphere at 900 . The effects of carbonization time on the microstructure, phase composition, and WC distribution of as―prepared nanocomposites were investigated by X―ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), and scanning transmission electron microscope (STEM). The electrocatalytic activities in alkaline solutions of these nanocomposites were evaluated in a three―electrode system by a powder microelectrode method. Due to the porous structure and high surface area of zeolite, the ball―milled AMT/zeolite precursor could be rapidly reduced in a mixed CH4/H2 atmosphere and then formed WC/zeolite nanocomposites. It was found that the active formed phase mainly composed of W2C and WC which were highly dispersed and extremely small―sized. The results also showed that the WC/zeolite nanocomposite obtained by carbonizing the ball―milled precursor for 4 h exhibited the best electrocatalytic activity, because this sample had smallest―sized and highest relative concents of tungsten carbide.